In modern wireless communications, there is a growing need for small-size, low-cost antennas for a wide range of portable and handheld devices. Currently, most antennas for mobile devices are fabricated by patterning copper traces on a substrate or stamped metal. These substrates are large and costly to fabricate. Another problem with regard to the size of the antenna may be for example, antennas for an Ultra High Frequency (UHF) spectrum (e.g., 470 MHz to 860 MHz) which are longer in size (e.g., a dipole antenna for 680 MHz is 20 cm in length by 1.5 cm wide) and that may be used for small size mobile devices such as, for example, laptop computers, handheld devices and the like.
Magnetic meta-materials have been explored for use as antenna substrates, but they are complex and expensive to manufacture. A study that used ferrite to increase the bandwidth of the antenna had as a side effect, a 7.5% reduction in the resonant frequency as compared to an air-core antenna. Another study obtained a mere 1.2% reduction in the resonant frequency. It is compelling to have small antennas in a space limited mobile device
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.